True/False
Indicate whether the
statement is true or false.
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1.
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Aristotle named atoms atoms.
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2.
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Nuclear decay can change one element into another one.
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3.
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Gamma decay is a form of nuclear radiation that consists entirely of energy, not
matter.
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4.
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The stability of a nucleus is determined by the ratio of electrons to
protons.
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5.
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In the notation  , 107 represents the atomic number and 47
represents the atomic mass of silver.
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6.
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A proton is a subatomic particle carrying a charge equal to but opposite that of
an electron.
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Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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7.
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Which scientist described an atom made of a solid positively charged substance
with electrons dispersed throughout it?
a. | Chadwick | c. | Rutherford | b. | Thomson | d. | Bohr |
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8.
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Which one is comprised of the other three?
a. | proton | c. | electron | b. | atom | d. | neutron |
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9.
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Which one(s) have a mass of 1 amu?
a. | electron | c. | proton and neutron | b. | proton | d. | electron and
proton |
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10.
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Which is the smallest part of an element that retains all the properties of the
element?
a. | proton | c. | electron | b. | neutron | d. | atom |
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11.
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Which is the correct symbol for this atom?
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12.
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Which is the number of protons in  ?
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13.
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Which is the number of neutrons in  ?
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14.
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Which element has 14 protons?
a. | Nitrogen | c. | Aluminum | b. | Silicon | d. | Sulfur |
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15.
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Which scientist measured the charge on an electron as 1.602 ´ 10-19 Coulombs?
a. | Democritus | c. | Rutherford | b. | Millikan | d. | Bohr |
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16.
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According to the modern concept of the atom, which are located in the nucleus of
an atom?
a. | electrons and protons | c. | neutrons and electrons | b. | protons
only | d. | protons and
neutrons |
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17.
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An atom has 23 protons and 29 neutrons. Which is the correct chemical symbol for
this atom?
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18.
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An industrially important element contains 26 electrons and rusts in the
presence of air and moisture. Identify the element.
a. | Aluminum | c. | Potassium | b. | Iron | d. | Sodium |
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Completion
Complete each
statement.
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19.
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A ____________________ is a subatomic particle that has mass nearly equal to
that of a proton, but it carries no electrical charge.
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20.
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Atoms with the same number of protons but different number of neutrons are
called ____________________.
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21.
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An alpha particle is _____________________ charged.
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22.
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A beta particle consists of a fast moving electron and has a(n)
_____________________ charge.
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23.
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James Chadwick showed that the nucleus also contained a neutral subatomic
particle known as the ____________________.
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24.
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Democritus believed that matter is made up of tiny individual particles known as
____________________.
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25.
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The number of protons in an atom is called the ____________________ of the
element.
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Short Answer, Worth 2 pts. each. Explain your answers in complete
sentences for full credit.
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26.
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What is the average atomic mass of this element? | Isotope | Mass (amu) | Percent Abundance | | Phosphorus-29 | 29 | 5% | | Phosphorus-31 | 31 | 71% | | Phosphorus-32 | 32 | 24% | | | |
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27.
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Identify the missing particle in the equation below. Justify your
response. 
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28.
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What is a nuclear reaction?
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29.
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Identify the element containing 34 protons.
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30.
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List the information needed to complete the table. | Composition of
Two Isotopes | | Isotope | Sulphur-32 | Calcium-44 | | Atomic number | a) | d) | | Mass number | 32 | e) | | Number of protons | 16 | f) | | Number of neutrons | b) | 24 | | Number of electrons | c) | 20 | | | |
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Problem, Worth 2 pts. extra credit each. Show your work/math for full
credit.
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31.
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An element X has two naturally occurring isotopes: X-79 (abundance = 50.69%,
mass = 78.918 amu) and X-81 (abundance = 49.31%, mass = 80.917 amu). Calculate the weighted atomic
mass of X. Also, identify the unknown element which exists as a reddish-brown gas and is a liquid at
room temperature.
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32.
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An element X has three naturally occurring isotopes: X-24, X-25, and X-26. The
atomic mass of X-25 is 24.986 amu and the relative abundance is 10.00 %. The atomic mass of X-26 is
25.982 amu and the relative abundance is 11.01 %.Given that the weighted atomic mass of the element X
is 24.305, calculate the mass contribution due to the isotope X-24 and identify the element.
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33.
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Calculate the number of protons, electrons, and neutrons in an atom of the
element Pb with mass number 207 and atomic number 82.
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Essay, Worth 4 pts of extra credit. Explain your answer, using complete
sentences, in a multi-sentence response.
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34.
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Democritus and Dalton proposed many similar points in their atomic theories.
Infer why Dalton’s were more accepted.
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